1. Field
The present disclosure relates to a novel purification process of emamectin benzoate and to compositions comprising emamectin benzoate purified using the same process.
2. Description of Related Art
Emamectin is a potent insecticide which controls many pests such as thrips, leafminers, and worms including alfalfa caterpillar, beet armyworm, cabbage looper, corn earworm, cutworms, diamondback moth, tobacco budworm, tomato fruitworm and tomato pinworm. Emamectin (4″-deoxy-4″-epi-N-methylamino avermectin B1a/B1b) is described in U.S. Pat. No. 4,874,749 and in Cvetovich, R. J. et al, J. Organic Chem. 59:7704-7708, 1994 (as MK-244).
U.S. Pat. No. 5,288,710 describes salts of emamectin that are especially agrochemically valuable. These salts of emamectin are valuable pesticides, especially for combating insects and representatives of the order Acarina. Some pests for which emamectin is useful in combating are listed in European Patent Application EP-A 736,252.
US2003/0068788 discloses a nucleotide sequence which encodes a P450 monooxygenase for making emamectin from avermectin. But, the purity of the resulting product is usually lower than 50%.
Emamectin is famous for its high efficacy and potency in insecticidal effect. However, the purity of emamectin used in commercial formulations nowadays is typically only around 95%. Due to the technical limitations, it is difficult to achieve a satisfactory purity without a dramatic increase in cost. Accordingly, there remains a need for a cost-effective purification method for emamectin benzoate which can be applied in the commercial industry.